Transformation by Rous sarcoma virus prevents acetylcholine receptor clustering on cultured chicken muscle fibers.

Acetylcholine receptors aggregate in the membrane of cultured chicken myotubes; the process of receptor clustering can be stimulated by exogenous factors that we, among others, have begun to characterize. Chicken myoblasts transformed by temperature-sensitive mutants of Rous sarcoma virus, such as tsNY68, fuse to form multinucleated myotubes at 42 degrees C, the nonpermissive temperature for transformation. However, tsNY68-infected myotubes do not cluster acetylcholine receptors at 42 degrees C, even in the presence of active clustering agents. This phenomenon is not merely a result of viral infection, since myotubes infected with a transformation-deficient viral mutant, td107A, behave like noninfected myotubes with respect to receptor clustering; thus, the effects of tsNY68 on the clustering process must be mediated by the src gene product. These experiments may provide a method of identifying essential elements of acetylcholine receptor clusters.